罕见病单个来看很少见，但总体影响约3亿人，且多为严重致残，甚至过早致死，其中约80%由基因缺陷引起。基因组学与基因药物的突破使越来越多疾病在技术上可治疗，但现实中患者很少得到治疗。原因在于经济学：为单个患者定制药物的研发与监管流程昂贵而缓慢，不适合规模化制药企业。自2018年以来，可能只有不到100种此类定制药物问世，通常由家庭通过慈善筹款自费支付。

英国药品和医疗产品监管局本月批准了一种新型临床试验，试图改变这一局面。10名患有危及生命的超罕见遗传性神经退行性疾病的儿童，将各自接受一种已知药物分子的独特变体。若试验成功，监管批准将针对“制造流程”而非逐一药物，使EveryONE Medicines可按需生产多种变体。美国食品药品监督管理局也在采取类似做法。该方法直面权衡：在几乎必然的持续痛苦面前，定制治疗的未知风险并非不合理。

流程性批准有望显著改善成本与速度。EveryONE Medicines估计，开发成本可从200万–300万美元降至低于100万美元，周期可从两到三年缩短至不足九个月。随着价格下降，需求将上升，公共医疗系统也可能参与。若再结合政府支付信号、更明确的监管，以及新生儿全基因组测序（英国已在开展大型试验），更多生物技术公司将进入这一领域。更多国家效仿，将加速这一良性循环并挽救更多生命。

Rare diseases are individually uncommon, but collectively affect about 300m people, are often severely debilitating, and frequently cut lives short, with roughly 80% caused by faulty genes. Breakthroughs in genomics and genomic medicines make more conditions treatable in principle, yet patients are rarely treated. The economics are the barrier: developing and regulating bespoke, one-patient drugs is costly and slow for firms built to scale. Since 2018, probably fewer than 100 such customised drugs have been made, usually paid for privately via charity.

Britain’s Medicines and Healthcare products Regulatory Agency approved a novel clinical trial this month to change that. Ten children with ultra-rare, life-threatening genetic neurodegenerative diseases will each receive a unique variant of a known drug molecule. If successful, approval would cover the manufacturing process rather than each drug, letting EveryONE Medicines produce many variants as needed. America’s Food and Drug Administration is adopting a similar approach. The logic confronts trade-offs: against near-certain suffering, the unknown risks of custom treatment are not unreasonable.

Process approval could sharply cut cost and time. EveryONE Medicines estimates development costs falling from $2m–3m to below $1m, and timelines from two or three years to under nine months. As prices drop, demand should rise, including from public health systems. Combined with clearer regulation, signals that governments will pay, and universal newborn whole-genome sequencing (now in large trials in Britain), more biotech firms should enter the field. As more countries follow, the virtuous cycle will accelerate and save more lives.